Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Lewisham Borough]
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Average results of the chemical and bacteriological examination of the water supply to the Borough of Lewisham for 1960 milligrams per litre (unless otherwise stated)
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Description of the sample | Ammonia nitrogen | Albuminoid nitrogen | Oxidised nitrogen (nitrate) | Chlorides as CI. | Oxygen abs. from permanganate (4 hrs. at 27°C) | Hardness (total) | Hardness (non-carbonate) | pH value | Electrical Conductivity (gemmhos) |
---|---|---|---|---|---|---|---|---|---|
Thames-derived filtered water | .038 | .080 | 4.0 | 28 | 1.26 | 254 | 68 | 7.8 | 525 |
Deptford | .012 | .034 | 7.8 | 36 | 0.16 | 368 | 130 | 7.1 | 725 |
Shortlands | .016 | .026 | 5.3 | 18 | 0.04 | 282 | 64 | 7.2 | 525 |
Darenth | .011 | .022 | 5.5 | 17 | 0.06 | 268 | 40 | 7.2 | 500 |
Wilmington | .012 | .028 | 7.8 | 21 | 0.10 | 284 | 54 | 7.1 | 550 |
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BEFORE CHLRINATION (RAW WATER) | AFTER CHLORINATION (WATER PASSING INTO SUPPLY) | |||||||
---|---|---|---|---|---|---|---|---|
Plate counts (average per ml.) Colonies counted on agar | Coliform count | Plate counts (average per ml.) on agar | Coliform count | |||||
37° C. (20-24 hrs.) | 22° C. (3 days) | Percenatge samples neg. 100 ml. | 37° C. (20-24 hrs.) | 22° C. (3 days) | Percentage samples neg. 100 ml. | |||
Coliform | E. Coli | Coliform | E. Coli | |||||
Thames derived filtered water | - | - | - | - | 8.6 | - | 99.57 | 100.0 |
Darenth well | 0.1 | 4 | 86.21 | 93.10 | 0.1 | 151 | 100.00 | 100.0 |
Deptford | 5.0 | 215 | 97.57 | 98.38 | 0.3 | 51 | 100.00 | 100.0 |
Shortlands No. 1 | 0.1 | 1 | 100.0 | 100.00 | 0.1 | 19 | 100.00 | 100.0 |
Shortlands No. 2 | - | 1 | 99.5 | 100.00 | ||||
Shortlands No. 3 | 1.0 | 25 | 99.1 | 100.00 | ||||
Wilmington No 2. Well | 0.1 | 45 | 94.38 | 99.20 | - | 11 | 99.61 | 100.0 |